QD: News Every Day--get the lead out

Lead levels previously considered acceptably safe may be linked to increased risk for adverse events, according to new research.

A study in this week's Annals of Internal Medicine used data from the National Health and Nutrition Examination Survey to evaluate whether lead levels in the "acceptable" range, that is lower than 1.21 micromoles per liter (less than 25 micrograms per deciliter), are associated with gout. Data from 2005-2008 on 6,153 patients 40 years of age and older who had no known kidney disease were examined. The main outcome measures were self-reported diagnosis of gout by a physician and serum urate levels, and the principal exposure variable was blood lead levels.

A gout prevalence of 6.05% was found among patients in the highest quartile of blood lead levels (mean, 0.19 micromoles per liter or 3.95 micrograms per deciliter), compared with 1.76% in patients in the lowest quartile (mean, 0.04 micromoles per liter or 0.89 micrograms per deciliter). In addition, each doubling of blood lead levels was associated with unadjusted odds ratios of 1.74 for gout and 1.25 for hyperuricemia.

After adjustment for renal function, diabetes, diuretics, hypertension, race, BMI, income and education level, the highest quartile of blood lead levels was associated with a 3.6-fold higher gout risk and a 1.9-fold higher hyperuricemia risk than the lowest quartile.

The authors noted that their results may have been affected by measurement error and that they didn't use measurements of lead levels over time, among other limitations. However, they concluded that even low levels of lead exposure may cause harm and that national goals for prevention, detection and removal of lead should be refined.

"These data suggest that there is no such thing as a 'safe' level of exposure to lead," they wrote.

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